The disclosure relates, in general, to a wheel for a motor vehicle.
The design of a wheel for a motor vehicle can have a number of implications for the appearance and performance of the vehicle itself. For example, the design of a wheel can affect fuel economy, vehicle handling, road noise, aesthetics, as well as a number of other factors. In general, a wheel for a motor vehicle may include a central hub portion including bolt holes or other features to enable the wheel to be mounted on to an axle of a vehicle such as with bolts or nuts. The wheel may also include a disk or spokes that extend between the hub and a rim portion of the wheel. The rim portion may include outboard and inboard flanges for mounting a tire.
With respect to wheel design, it is generally desirable to improve the overall performance of a vehicle by reducing the weight of the wheel while maintaining the lateral stiffness of the wheel, which can have an effect on the dynamic response of the vehicle. However, a reduction in wheel weight may often result in a decrease in lateral stiffness. Factors that contribute to the lateral stiffness of a wheel may include the distance from the hub of the wheel to the rim, the number and type of spokes or other connection between the hub and the rim, the thickness of the various wheel components, and so forth. For example, a wheel with more spokes or thicker spokes may results in a wheel with greater lateral stiffness.
In another aspect, it is generally desirable to improve road noise performance by separating first and second modes of wheel natural frequency from a tire cavity resonance area. In general, a number of factors may contribute to the noise level with a cabin or passenger compartment of a motor vehicle. For example, sources of cabin noise associated with the wheel of a motor vehicle can include external noise produced when the tire of a wheel meets the road surface. More particularly, a tire mounted to the rim of a wheel may define an acoustic cavity with a characteristic frequency based at least partially on an average radius of the cavity. The sound that is produced in the air cavity inside the wheel is the result of a standing wave being excited which is related to the natural frequency (resonance frequency) of the wheel.
Some wheel designs call for one or more additional components in order to reduce the natural frequency sounds in wheels that originate in the acoustic air cavity inside the wheel. One example method for suppressing sound inside wheels includes the use of a sound-absorbing material or one or more resonators arranged in connection to the sound absorbers inside the tire. Other example devices include a sound shield that is placed on the outside of the wheel or resonators placed in the wheel housing. However, these devices may add to the production and material cost of the wheel as well as increase the overall weight of the wheel.